Cutting edge member



1965 E. o. COOKE 3,197,895

CUTTING EDGE MEMBER Filed March 18, 1963 INVENTOR. EDGAR OLIN COOKE ATTORNEY United States Patent 3,197,895 CUTTING EDGE MEMBER Edgar Olin Cooke, Lynwood, Calif. (9634 Washburn Road, Downey, Calif.) Filed Mar. 18, 1963, Ser. No. 265,966 1 Claim. (Cl. 37-143) The present invention relates generally to the field of earth moving equipment, and more particularly to an improved cutting edge member that will remain in a bolted position on a power-driven moldboard, even after the member has been drastically thinned due to abrasive wear.

As is well known, the cutting and movement of earth on construction projects is normally carried out by the use of such equipment as power-operated scrapers, carryalls, bulldozers of the straight, angle and U-type, motor graders, trenching machines, draglines, bucket shovels, back hoes, adapters, teeth and shanks, as well as skip loaders in certain instances. To .protect the mol-dboards of such equipment which may be powered by high horsepower engines or by the use of one or more tremendously high-powered tractors, from abrasive contact with the severed soil, the lower edge of the moldboard is provided with one or more cutting edge members removably mounted thereon which contact the earth being moved to push it to a desired location either inside the earth mover as in the case of a carryall, or forwardly of the mover when a bulldozer is used.

During this pushing operation the severed material moves along the forward face of the cutting edge member, and in so doing tends to wear the member thin due to the abrasive action thereof. In addition, the cutting edge member is subjected to intermittent stresses and jolts as it contacts rocks, stones, and the like during the earth moving operation.

Normally, the cutting edge member is removably affixed to the moldboard by a number of longitudinally spaced bolts and is subjected to two hazards which may shorten the useful life thereof. When it is being used on rough and rocky terrain the cutting edge member is subject to being displaced from the mold-board due to shearing ofi of the bolts, or it may be dropped from the moldboard as a result thereof. In such a contingency, the cutting member becomes mixed with some twenty to sixty yards of earth, sand, or debris, and it is most difficult to locate it amongst this material in the fill area to which it has been moved.

Cutting edge members of the type described must be formed from a relatively high-grade abrasion-resistant steel, which makes them relatively expen ive, running from $50.00 to $65.00 a section, particularly in view of the fact that on large bulldozers a commonly employed assembly comprises four such members. As the cutting edge members are subjected to the abrasive action of the dirt and sand being moved, the cutting edge members tend to wear thin, leaving the boltheads exposed to abrasive action as well. The boltheads then wear down and thereafter the stress set up by the cutting edge member on the thinned boltheads tends to bend the bolts whereby they slip through the openings in the cutting edge member and fall from the moldboard to be mixed with the earth being moved.

A major object of the present invention is to provide a cutting edge member in which substantially greater cylindrical surface areas thereof are supported by the shank-s of the supporting bolts to minimize the cracking or breaking of the member at these areas of support, as well as to minimize shearing of the bolts and provide sets of quadrantly spaced body shoulders which fully engage intermediate portions of the bolt-s between the heads and shanks thereof to permit maximum wear on the boltheads prior to failure of the bolts to hold the cutting edge member in a predetermined position on the moldboard.

Another object of the invention is to provide a cutting edge member that has a substantially long-er life than devices of this nature available heretofore in that failure by abrasion, wearing off of the heads of the supporting bolts, bending of the bolts, and shearing off of the bolts is minimized.

A still further object of the invention is to provide a cutting edge member in which that surface thereof in contact with the shanks of supporting bolt is drastically increased, and one that is free of sharply defined pressure areas whereby the tendency of the bolts to shear off when subjected to stress is minimized as the cutting edge member severs earth, rock, and the like from the soil.

These and other objects and advantages of the invention will become apparent from the following description of the cutting edge member, and from the accompanying drawing illustrating the same, in which:

FIGURE 1 is a perspective view of a moldboard such as used on a bulldozer, with one of the cutting edge members removably mounted thereon, disposed between two removably mountable end pieces;

FIGURE 2 is an enlarged front elevational view of a fragmentary portion of the cutting edge member showing one of the bolts in place therein;

FIGURE 3 is a transverse cross-sectional view of a portion of the cutting edge member and a mold-board, together with one of the supporting bolts and associated nuts, taken on line 3-3 of FIGURE 2;

FIGURE 4 is a front elevational view of one set of four body shoulders defined in the cutting edge member as seen through a bolt hole formed therein;

FIGURE 5 is a transverse cross-sectional view of a portion of the cutting edge member, taken on line 5-5 of FIGURE 4;

FIGURE 6 illustrates a first step in forming the cutting edge member;

FIGURE 7 illustrates a second step in forming the cutting edge member; and

FIGURE 8 is a side elevational view of one of the bolts used in holding the cutting edge member in place on a moldboard.

With continuing reference to the drawing for the general arrangement of the invention, it will be seen in FIGURE 1 that a conventional moldboard structure A is provided, which in this particular instance is part of a Caterpillar No. 6A bulldozer, manufactured by the Caterpillar Tractor Corporation of Peoria, Illinois. The moldboard A has two cast cutting edge plates B bolted to the lower outer edges thereof. A cutting edge member C is removably afiixed to the lower forward portion of moldboard A, and may be either a single elongate metallic body as shown, or comprise a number of elongate sections (not shown) disposed in end-to-end relationship on the moldboard.

A number of sets of longitudinally spaced body shoulders D are formed within cutting edge member C, one of which is shown in FIGURE 4. Each set of body shoulders D is defined by four quadrantly spaced triangular surface areas 10. Each area 10 is generally triangular and defined by two straight sides 12 and 14 at right angles to one another, which are joined by an arcuate hypotenuse 16. Each area 10, as can best be seen in FIGURE 5, slopes inwardly and rearwardly towards the moldboard A when the cutting edge member is mounted thereon, as illustrated in FIGURE 1. The four arcuate hypotenuses 16 partially define the forward extremity of a transversely positioned circular bore 18 3 formed in the cutting member C, as best seen in FIG- URE 3.

A bore 20 (FIGURE 5) of square transverse cross sectionis formed in cutting edge member C and is in axial alignment with the bore 18. The sides 26a of bore are tangential relative to the circular bore 18. The forward edge of bore 20 develops into a forwardly and outwardly tapering surface 22. A number of longitudinally spaced ring-shaped recesses 24 are formed in the forward face of cutting edge member C, each of which is in coaxial alignment with one of the tapered surfaces 22' and effects a circumferentially extending junction line 26 therewith.

A number of bolts B, one of which is shown in FIG- URE 8, are provided, which with nuts F serve to removably support the cutting edge C from the moldboard A as shown in FIGURE 1. Each bolt E has a shank 27 on which external threads 28 are formed, and that extends through one of a number of longitudinally spaced transversely positioned bores 30 formed in moldboard A.' Each bolt E also includes a head G that is defined by a fiat, forwardly disposed circular surface 32 which develops into a thin ring-shaped surface 34 that in turn develops into a tapered surface 36. In addition bolts E include an intermediate portion 38 of square transverse cross section located between the head 32 and shank 26.

The intermediate bolt portion 38 is partially defined by four side walls 40 which are disposed at right angles relative to one another. Four triangular areas 42 are formed on the intermediate portion 38 and extend inwardly and'rearwardly to merge at the rear extremity of .the forward portion of shank 26. Shank 26 is of such transverse cross section as to fit snugly within the confines of one of the bores 18 and one of the bores 30 in moldboard A that is in coaxial alignment therewith.

The intermediate portion 38 of each bolt E is positioned in one of the square bores 20, with the triangular areas 42 being in abutting contact with one of the body shoulder areas 10. The areas 42 and areas 10 are complementary to make such abutting contact possible. When the areas 42 are in such abutting contact with areas 10, the tapered surface 36 of each bolt E is in abutment with thesurface defining one of the tapered bores 22. The width of the ring-shaped surface 34 is substantially less than the depth of one of the recesses 24, and as a result, when the bolt is positioned as above described and shown in FIGURE 3, the forward surface 32 of bolt head G is disposed rearwardly a substantial distance from the forward surface 44 of cutting edge member C. This rearward positioning of the forward surfaces 32 of bolt heads G relative to the surface 44 tends to lessen the abrasive action to which the bolt heads are subjected as earth and the like is moved by cutting edge member C.

When each bolt F is disposed in the cutting edge member C, as well as in the bore 30 of moldboard A, it is held in this position by tightening one of the nuts F on the threads 28 to bring it into contact with the rear surface 46 of the moldboard. The cutting edge member C is subjected to a force that would tend to rotate it in a clockwise direction relative to the moldboard A when the lower edge 48 of the cutting edge member is in cutting contact with the ground surface. When the cutting edge member C is subjected to such a force, the surface thereof defining bore 18 is in pressure contact with the shank 26 and there are no sharp edges which tend to sever the shank. The force exerted by the cutting edge member C on each shank 26 is distributed over a large area, whereby the life expectancy of each bolt E is substantially increased.

Any tendency on the part of the cutting edge member C to pivot in a clockwise direction relative to the moldboard A is resisted by the tapered surface 36 and areas 42 which are in pressure contact with the surface de fining bore 22 and areas 10 respectively. In FIGURES 3, 5 and 8 it will be seen that the surfaces 36 and the surfaces defining bores 22 are disposed forwardly of areas 42 and 10, and that the areas 42 and 10 serve to cooperatively hold the cutting edge member C on moldboard A, even after the heads G have been completely removed from the bolts E by abrasion. I

In actual use, during which the cutting edge member is subjected to abruptly applied stresses, small scratches and imperfections in the surfaces defining the recesses 24, tapered bores 22, square bores 20 and body shoulder surfaces 10 may serve as focal points from which cracks can start as the metal of the cutting edge member C fatigues. Accordingly, it is desirable that the portion of the metal defining the recesses 24, tapered bores 22, square bores 20 and body shoulder surfaces 10 be under compression, and as a result at all times tend to m n mize the formation of any cracks that may tend to originate in these surface areas.

To attain the above result, a number of bores 50 are drilled through cutting edge member C, the centers of which are the same as the centers of bores 18.. Each of the bores St is no larger in transverse cross section than one of the bores 18. Each bore 50 is countersunk to provide a beveled area 51 adjacent face 44. A punch 52 is provided that includes a cylindrical portion 54 wh ch is forced downwardly through bore 50. Above portion 54 thereof, punch 52 includes a body 56 of such configuration as to pressure form the bores 20 and 22, recesses 24 and body shoulders D in the cutting edge member C when brought into forceful contact therewith. As the punch 52 moves downwardly through the cutting edge member C, the metal of the cutting edge member surrounding the punch cold floWs and permanently deforms, but in the deformed state still retains substantial elasticity. Upon removal of punch 52 from the cutting edge member C, the elasticity of the metal of the member tends to cause the surface areas of the bores 20 and 22, recesses 24, and body shoulders D, hereinafter referred to jointly as a zone, to decrease slightly in area from that possessed when initially formed. This three-dimensional expansion of the metal and resulting decrease in area of the bores, recesses and shoulders, places longitudinally spaced zones of the metal of the cutting member C under compression, and tends to minimize possible development of cracks therein of such size as to cause failure of the member C. Thus, the cutting edge member C will have a longer life than those available heretofore, for it will not be displaced from moldboard A due to abrasive wear simply because the bolt heads G have been worn from the bolts E, nor will the cutting edge member be inclined to fail due to development of fatigue cracks in the region adjacent bolts E.

The cutting edge member C is preferably formed from a hard, tough steel, or like material. The use and operation of the invention have been described in detail hereinabove, and need not be repeated.

Although the present invention is fully capable of achieving the objects and providing the advantages hereinbefore mentioned, it is to be understood that it is merely illustrative of the presently preferred embodiments there of and I do not mean to be limited to the details of construction herein shown and described, other than as defined in the appended claim.

I claim:

A cutting edge. member adapted to be held on a moldboard by a plurality of bolts having heads, which mem- 'ber comprises an elongate rigid metal body having a plurality of longitudinally spaced metal zones that have been cold worked, but with said metal after said cold working possessing sufficient elasticity that it expands three-dimensionally to place said metal under compression whereby said zones are resistant to development of cracks therein, with each of Said zones being at least partially defined by a recessed ring-shaped surface, a tapered surface that extends rearwardly in said body from said ringshaped surface, a square bore that extends rearwardly from said tapered surface, a bore of circular cross section that extends rearwardly from said bore of square cross section, and four circumferentially spaced body shoulders in said body adjacent a junction between said bores of square and circular cross section, with said ringshaped surfaces, tapered surfaces, square bores, circular bores, and body shoulders being of such dimensions as to permit snug engagement thereof by said heads when said bolts are extended therethrough, and with said body shoulders serving to hold said bolts in said body, even after that portion of said body forwardly of said body shoulders and a substantial portion of said head has been worn away.

References Cited by the Examiner UNITED STATES PATENTS 1,633,057 6/27 Wold 37--143 6 1,989,274 1/35 Gustafson 37--143 2,018,392 10/ 35 Willink. 2,424,087 7/47 Focke. 2,831,275 4/58 Kirnsey 37-141 FOREIGN PATENTS 721,679 1/55 Great Britain.

OTHER REFERENCES Catalog No. 47 of the Schaberg-Dietrich Hardware Co., 232 No. Washington Ave., Lansing 4, Mich., copyright 1947 by R. R. Donnelley and Sons Co.; Call No. TI 1190-8 35-1947, p. 289 relied on.

15 ABRAHAM G. STONE, Primary Examiner.

BENJAMIN HERSH, WILLIAM A. SMITH, III,

Examiners. 

